The invention relates to a hydraulic support in the form of a hydraulically damped elastomer support with an inner supporting part and an outer supporting part, concentric with the latter, and an annular elastomer body which is arranged as a spring between these supporting parts and in which there are formed hydraulic chambers which communicate with one another via hydraulic restrictor sections and between which hydraulic medium is exchanged when the supporting parts move relative to one another in the axial or radial direction. There preferably are at least two groups of chambers, which are spaced apart in the circumferential direction of the supporting parts and which each have at least two chambers situated adjacent to one another in the axial direction. The restrictor sections connect the chambers of each group to one another and in each case connect one chamber of each group to the corresponding chamber of another group.
A hydraulic support of this kind is the subject matter of German Patent Document DE 41 17 128 A1. There, the elastomer body is arranged between the outer supporting part, which is designed as a sheet-metal part, and an intermediate sleeve, which likewise consists of sheet metal and which, for its part, forms a seal directly on the inner supporting part and is held axially secured. The restrictor sections can be arranged as channels in the elastomer body and/or between the intermediate sleeve and the inner supporting part, which for this purpose is provided on its outer circumference with corresponding grooves or the like which communicate via openings in the intermediate sleeve with the hydraulic chambers recessed into the elastomer body.
In the case of this known hydraulic support, it is, on the one hand, possible for the cross-section of the restrictor sections arranged in the elastomer body and hence the restriction provided by them to vary. On the other hand, sealing problems can arise with the restrictor sections arranged between the intermediate sleeve and the inner supporting part.
One advantage of this known hydraulic support consists in the fact that, in the case of radial and axial relative movements between the outer and the inner supporting part, hydraulic medium is exchanged between different chambers and hence via different restrictor sections, which can be differently tuned in order to effect stronger damping in the radial or axial direction, at different vibration frequencies if required.
In order to achieve a greater displacement of hydraulic medium in the case of axial relative movements between the supporting parts too, the proposal of German Patent Document DE 41 71 128 A1 is that each group of chambers should have a chamber which is arranged between a tapered inner circumferential region of the outer supporting part and the tapered outer circumference of a shaped plate arranged on the inner supporting part. In the case of axial relative movements between the outer and the inner supporting part, the axial spacing between the tapered inner circumferential region and the opposing tapered outer circumferential surface changes.
A functionally similar hydraulic support is the subject-matter of German Patent Document EP 04 52 169 A1. Here, the supporting parts are designed as mutually concentric sleeve parts, one end of each of which is provided with a flange. Arranged within the elastomer body which fills the clearance between the flanges and the sleeve parts there is a first annular chamber between the flanges and a second annular chamber in the region of the sleeve ends remote from the flanges, the second annular chamber communicating with the first annular chamber via an axial channel formed in the inner supporting part. Arranged axially between the two annular chambers, between the sleeve parts, there are two chambers which are situated diametrically opposite one another and are connected to one another via another channel formed in the inner supporting part. The two latter chambers can furthermore be connected to the annular chambers via additional channels.
German Patent Document DE 37 22 132 A1 discloses a further hydraulic support, the elastomer body of which is arranged between the outer supporting part and an inner sleeve held in a sealing manner on the inner supporting part. This hydraulic support has just two hydraulic chambers, which are accommodated in recesses in the outer circumference of the inner supporting part and directly adjoin the elastomer body in the radially outward direction since the inner sleeve has apertures in the region of the above-mentioned depressions. A restrictor section connecting the two chambers can be formed as a transverse hole in the inner supporting part or between the inner sleeve and the inner supporting part, which has a depression in the circumferential direction in the region of the restrictor channel.
In the case of a hydraulic support known from German Patent Document DE 41 06 451 A1, three hydraulic chambers are formed between an outer supporting part designed as a cylindrical sleeve and an inner supporting part likewise designed as a cylindrical sleeve, the hydraulic chambers being arranged within an elastomer body arranged between the supporting parts. Of these hydraulic chambers, two are provided radially to the outside and one within an annular part embedded in the elastomer body, the two chambers arranged outside the annular part being separated from one another by a thin membrane, while the two other chambers are connected to one another via a restrictor section which passes through the elastomer body.
An object of the invention is to provide a new design for a hydraulic support of the type stated at the outset, which design can be implemented economically.
According to the invention, this object is achieved by providing an arrangement wherein the elastomer body has embedded in it or vulcanized into it near to its outer circumference a reinforcing sleeve which is surrounded in leaktight fashion by the outer supporting part, which rests on an elastomer layer at the outside of the reinforcing sleeve, exerting pressure on it, wherein apertures in the reinforcing sleeve and recesses open to the apertures in the elastomer body are provided for the chambers, and wherein the restrictor sections are formed as a transverse hole in the inner supporting part and as channels running between the outer supporting part and the reinforcing sleeve in beads of the outer supporting part.
The invention is based on the general idea of reinforcing the outer supporting part, which can be constructed in a manner which is fundamentally known as a sheet-metal part, by means of a reinforcing sleeve embedded in the radially outer region of the elastomer body, making it possible without further measures to achieve the same mechanical loadability as with the inner supporting part, typically designed as a solid part. This simultaneously achieves the advantage that restrictor sections running between the outer supporting part and the reinforcing sleeve can be readily produced by deformation of the sheet-metal material of the outer supporting part and hence at an easily accessible location and that they are arranged between rigid parts. The transverse hole optionally provided as a restrictor section in the inner supporting part remains readily accessible until the outer supporting part is fitted since the mouths of this transverse hole, which are arranged in the associated hydraulic chambers, are freely accessible via the apertures present in the reinforcing sleeve in the region of the hydraulic chambers.
According to a particularly preferred embodiment of the invention, it is envisaged that the inner supporting part should have a region with an essentially cylindrical--or slightly tapered--outer circumference and a region with an outer circumference which has a pronounced taper, and that the outer supporting part should have regions with a cylindrical--or slightly tapered--and conical inner circumference which are spaced apart from the said outer supporting part by the elastomer spring arrangement.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.